Lidocaine relaxation in isolated rat aortic rings is enhanced by endothelial removal: possible role of Kv, KATP channels and A2a receptor crosstalk

Figures

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  Fig. 1. A graphical scheme of the rat thoracic aorta ring apparatus for isometric force measurements, receptor sensitivity and smooth muscle-endothelial interactions. See Methods for details

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  Fig. 2. Concentration response curves to lidocaine in intact and denuded isolated rat aortic rings. Relaxation is expressed as percent of maximal relaxation to 100 μM papaverine. Points represent mean ± S.E.M of aortic rings. *P < 0.05 statistical difference in responses between the intact and denuded rings. Lidocaine concentrations are on a log scale. Total animals n = 12

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  Fig. 3. Concentration-response curves to lidocaine with and without the presence of L-NAME + indomethacin in intact isolated rat aortic rings. Relaxation is expressed as percent of maximal relaxation to 100 μM papaverine. Points represent mean ± S.E.M of aortic rings. *P < 0.05 statistically different in the presence of L-NAME + indomethacin compared to control on intact rings. Lidocaine concentrations are on a log scale. Total animals n = 12

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  Fig. 4. Concentration-response curves to lidocaine with and without the presence of specific ion channel blockers in intact isolated rat aortic rings. a In the presence of 1 mM 4-aminopyridine. b In the presence of 1 mM 5-Hydroxydecanoate. c In the presence of 10 μM glibenclamide. d In the presence of 100 μM ouabain. Relaxation is expressed as percent of maximal relaxation to 100 μM papaverine. Points represent mean ± S.E.M of aortic rings in the presence of L-NAME and indomethacin. *P < 0.05 statistical difference in responses between the presence and the absence of inhibitors on intact rings. Lidocaine concentrations are on a log scale. Total animals n = 16

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  Fig. 5. Concentration-response curves to lidocaine with and without the presence of specific ion channel blockers in denuded isolated rat aortic rings. a In the presence of 1 mM 4-aminopyridine. b In the presence of 1 mM 5-Hydroxydecanoate. c In the presence of 10 μM glibenclamide. d In the presence of 100 μM ouabain. Relaxation is expressed as percent of maximal relaxation to 100 μM papaverine. Points represent mean ± S.E.M of aortic rings in the presence of L-NAME and indomethacin. *P < 0.05 statistical difference in responses between the presence and the absence of inhibitors on intact rings. Lidocaine concentrations are on a log scale. Total animals n = 16

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  Fig. 6. Concentration-response curves to lidocaine with and without the presence of adenosine A2ab receptor blockers in intact and denuded isolated rat aortic rings. a (Adenosine A2a receptor antagonist) In the presence of 100 μM 8-(3-Chlorostyryl) caffeine. b (Adenosine A2b receptor antagonist) In the presence of 10 μM PSB-0788. Relaxation is expressed as percent of maximal relaxation to 100 μM papaverine. Points represent mean ± S.E.M of aortic rings in the presence of L-NAME and indomethacin. *P < 0.05 statistical difference in responses between the presence and the absence of inhibitors on intact rings. Lidocaine concentrations are on a log scale. Total animals n = 16